Distribution of fluids



Feb. 26, 1957 FREER 2,782,739

DISTRIBUTION OF FLUIDS Filed April 22, 1955 4p 4 6 l r r 1 l l Ava;flame! 444mm. I4 (75% -Haz,

AG NT- lava/1% DISTRIBUTION OF FLUIDS John G. Freer, Anaheim, Calif.,assignor to Union Oil Company of California, Los Angeles, Calif., acorporation of California Application April 22, 1955, Serial No. 503,286

14 Claims. (Cl. 111-7) This invention relates to a method and apparatusfor the dispensing of fluids and in particular relates to the dispensingof a plurality of streams of fluid from a single source wherein each ofthe plurality of flows has a predetermined flow rate. Specifically thisinvention relates to an improved method and apparatus for the divisionof a single fluid stream into a plurality of individual streams eachhaving a flow rate bearing a predetermined relation to the flow rates ofthe other streams. The present invention is particularly related to animproved method and apparatus for distributing liquids in a plurality ofindividual streams on sloping ground, either through subsurface orsurface application, and in which the disturbing influences of theliquid head difierences can be completely eliminated, or, in a practicalsense, eliminated to any desired degree depending upon the choice ofspecific gravity for the compensating fluid and the exactness of thephysical arrangement.

The controlled rate dispensing of fluids, either gaseous or liquid, in aplurality of closely controlled streams of interrelated flow rate from asingle flow source, is involved in many industrial and agriculturaloperations. A few of these include the injection of reagent fluids inseparate streams and at several difierent locations in a chemicalreaction process, the filling of a plurality of containerssimultaneously with predetermined volumes of liquid such as in thecanning of lubricating oils, vegetable juices, and in the bottling ofliquid commodities such as beverages, the injection of gaseous or liquidfertilizers such as ammonia or ammonium hydroxide simultaneously at aplurality of either aboveground or underground delivery points, and thelike. Other liquid synthetic fertilizers which may be so dispensedinclude aqueous solutions of the soluble salts of ammonia, potassium,phosphorus, sulfur, and the like and these may be applied in a pluralityof streams simultaneously to several individual streams of irrigationwater aboveground, or in an underground application as in combinationwith some sort of conventional soil tilling operation or as a separateoperation.

l-leretofore each fluid stream in the plurality was individuallyadjusted by providing a main conduit opening froma storage container anddelivering fluid into a manifold or header from which a plurality ofbranched outlet conduits opened. In each of such bnanch conduitswasusually located some sort of flow controller such as. a valve or anorifice. This arrangement has a number of disadvantages. The principalproblem when the flow control device is of the fixed area type, as arethe common sharp edge and short tube type orifices and individualmanually operated control valves, is that with attempted increases influid delivery rate by raising the source pressure, this source pressureincreases at a much greater rate than does the flow it initiates. Indispensing of liquids, positive displacement pumps of the piston,diaphragm, bellows, or gear type are conventionally used in order tometer the total liquid output accurately at the pump. An attempt toincrease the total delivery rate through fixed size restriction openingsby increasing pump nited States Patent speed or stroke, rapidly causesan excessive build-up in pressure at the pump discharge. These pressurebuild-ups are readily capable of and frequently result in rupture damageto the pump or the equipment through which the liquid is distributed.

There is an additional problem in the application of liquid fertilizersor other liquids to the soil involving flow rate variation in theindividual streams caused by diflerences in liquid head when themanifold conduit from which the liquid is distributed is not level. Thisdifliculty may arise either when distribution of the liquid in aplurality of streams is attempted into a plurality of irrigation waterflows at different levels along the slant height of a hill or frommoving equipment which is drawn more or less along the contours of thehillside. In either case there may be an appreciable diflerence inelevation between the upper and lower ends of the main distributingconduit so that the actual pressure initiating the flow of theindividual liquid streams, and hence their flow rates, will vary widely.The present invention as hereinafter more fully detailed successfullyeliminates this problem by employing a plurality of specially designedliquid dividers and flow controllers which are provided with acompensation means whereby the flow rate of each of the plurality ofliquidstreams is completely independent of the aforementioned variationsin liquid head. Furthermore the liquid divider and flow controller ismodified so as to produce a plurality of individual liquid streams, thevolumetric flow rate of each of which varies in a linear fashion withthe pressure of the liquid applied at the divider inlet, and whichexhibits a very eflective damping action on pulsating flows from thepump.

The present invention is therefore directed to an improved method andapparatus for the division of a fluid into a plurality of streams andthe distribution of said streams at predetermined variable rates inwhich the aforementioned dilficulties are avoided.

It is an object of the present invention to provide a fluid splittingand distributing device adapted to the division and delivery of aplurality of fluid streams at equal or otherwise predeterminedindividual flow rates. I It is a more specific object of this inventionto provide a device for the automatic regulation of the back pressure ofthe inlet fluid flow in a fluid dispensing device delivering a pluralityof fluid streams while permitting predetermined division of the flowthrough a plurality of variable orifices.

It is a further object of this invention to provide an improved liquiddividing and distribution system in which the flow rate of individualliquid streams is linearly variable with applied liquid pressure towithin about plus or minus 1-3% and in which the individual flow ratesare, to any desired degree, independent of liquid head eifects at thedivider inlet permitting uniform side hill application.

It is a more particular object of this invention to provide an improveddevice for the dispensing of liquids in a plurality of streams, such asin the dispensing of liquid fertilizers into irrigation water or intothe ground, in which the individual liquid flow rates have a linearrelation to the inlet liquid pressure and do not vary with elevation ofthis device relative to the supply point at which the liquid to bedistributed is introduced into the manifold from which the individualliquid streams are taken to the device.

Other objects and advantages of the present invention will becomeapparent to those skilled in the art as the description and illustrationthereof proceeds.

Briefly .the present invention comprises in combination a fluiddispensing system comprising a container suitable for storage of thefluid to be dispensed, a fluid pressure control means such as a valve ora variable delivery 3 pump connected in fluid receiving relation to thecontainer, and an especially designed spring loaded variable orificedevice having a single fluid inlet and a plurality of fluid outlets, theoutlets each containing an orifice of predetermined size whosecross-sectional area open to fluid flow is opened or closed to a degreedepending upon the pressure of the inlet fluid. A movable valve memberis r-eciprocably disposed adjacent the inlet ends of a plurality oforifices and is spring loaded by means of at least one adjustableloading spring whereby the valve member is biased toward a position atwhich all of the orifices are normally closed.

The storage container referred to above and the pump and the variableorifice device or devices may be mounted upon any suitable kind ofmoving farm machinery adapted to be drawn or driven across the land towhich the liquid is applied. The pump may be provided with its own primemover but preferably is directly driven from a ground contacting wheelso as to discharge any predetermined quantity of liquid as a function ofthe ground area covered. In the specific case illustrated, a transversetool bar is supported from the trailer and in turn supports a pluralityfrom 4 to 36 or more injection shanks each extending to points from 6 to12 inches below the ground surface. A transverse liquid supply manifoldis also provided parallel to the tool bar. Each injection shank isprovided with a conduit for fluid flow which opens into the shank from aliquid dividing and flow controlling device hereinafter more fullydescribed, and which devices in turn receive fluid from the supplymanifold. These devices are further provided with means for compensatingfor liquid head eflects on the individual liquid flow rates when theequipment is drawn along a hillside contour while the tool bar andsupply manifold extend along the slant height of the hill.

It should be understood however that the invention is not restricted tomoving farm equipment, because it may be employed to dischargeindividual liquid streams into a plurality of irrigation water flowsmoving in a plurality of more or less parallel courses disposed side byside at different elevations along a hillside. In either case thecompensation for liquid head effects has proven eminently successful inmaintaining the individual liquid flow rates at equal values or atvalues having any predetermined relation to one another independent ofdifferential liquid hydrostatic head effects.

An essential element of the apparatus of this inventron, as indicatedabove, consists in a liquid flow divider and controller. In theapparatus of this invention several of these flow dividers may beemployed depending upon the number of individual liquid streams desired.As briefly indicated above, this divider consists of a pressureresistant valve body having an inlet channel, a movable valve memberdisposed within the channel, a plurality of orifices opening laterallyfrom this channel and adapted to be closed by the movable. valve member,and a diaphragm attached to the valve member within the valve body.

The inlet pressure of the fluid to be divided and dispensed acts on adiaphragm integrally attached to the valve member and acts against theloading spring which in one modification causes the valve member to moveafter a preset minimum pressure is reached so as to expose at least aportion of each of the orifices and permit a small amount of fluid toflow through the orifices in a predetermined ratio. At a constant inletfluid flow rate, the reciprocable valve member reaches and maintains anequilibrium position such that the quantity of fluid flowing through theorifices dissipates most of the inlet pressure by producing a pressuredrop equal to the pressure difference between the pressure necessary toopen the orifices against the loading spring and the outlet pressurehead of the fluid into which the flow is being delivered by thedistributing device. The loading spring,

being adjustable, permits a predetermined minimum flow pressure to beset which the pressure source must exceed before the variable orificesare opened at all. For purposes of the present discussion this will bedefined as Po, and the pressure source will be a pump. When the outletpressure of the pump, which usually is substantially the same as thefluid inlet pressure at the distributing device and herein defined asPr, exceeds the preset minimum value Po by an amount equal to AP, thisexcess inlet pressure AP opens the orifices by an amount sufiicient topermit a fluid flow through each orifice, the quantity of which isgoverned by the difference between the inlet pressure Pr and the outletpressure head. With further increases in pressure effected to increasethe fluid delivery rates, the higher values of AP cause the valve memberto move to open greater areas of the orifices resulting in increasedfluid flows through each orifice sufficient to dissipate the highervalue of Pl. At maximum rate, the orifices are opened entirely to permita fluid flow which is substantially equal to the capacity of the pumpthus preventing the build-up of destructive pressures under anyconditions of fluid flow desired. In this manner the maximum pressureand energy necessary to discharge a certain volume of liquid areconsiderably reduced relative to the fixed area flow restrictions. It isto be noted that a spring with a low spring constant (pounds per inchdeflection) will permit the maximum flow rate with less increase in Pithan will occur using a spring with a high spring constant;

A slightly modified and highly desirable form of liquid dividercomprises one in which a primary and a secondary loading spring operateagainst the movable valve element, the primary spring being adjusted sothat it applies no compressive force against the valve member in theclosed position. The result obtained by this modification is theimmediate opening of the valve with applied pressure against arelatively light force of the secondary spring whereby a nearly perfectdirect proportionality of individual flow rate with applied pressure isattained as illustrated in Figure 5 With the valve element seated, onlythe secondary loading spring exerts a relatively light load. on thevalve element. The primary loading spring being normally shorter is notplaced in compression until the applied fluid pressure raises the valveelement against the compression force of the secondary spring. The primary spring is selected to have a relatively high spring constant, thatis one of the order of 10 to times that of the secondary spring. Thedevice is adjusted so that when the secondary spring seats the valveelement, the primary loading spring is under no compression forcewhatsoever and being shorter or otherwise adjusted to have a smallclearance from its stop at one end. The main purpose of the secondaryspring is to seat the valve member when the delivered flow has stopped,which eliminates syphoning of the system. The secondary effect is thatwith low applied pressures the valve element opens by compressing thesecondary loading spring first, thereby giving a linear characteristicat low applied pressures and flow rates. With further increases inpressure, the restraining force is substantially entirely supplied bythe primary loading spring which maintains complete linearity over thehigher applied inlet pressures. Extensive testing of this device hasshown it capable of producing individual liquid flow rates which arelinear over their entire range to an accuracy of within 1 to 3%. Thediaphragm, valve element, and compression spring( s) form a dampedspringmass system with an approximate natural frequency of C. P. S. forthe specific models tested. This situation implie that pulsating flowsinto the distributor at or near 150 C. P. S. will get the least dampingaction. The frequencies were limited to the range 300 to 4400 C. P. S.,and over that'range pulsation was nearly completely eliminated in theoutlet flow. It also appears that more effective damping is obtained athigh flow rates due to seeondary damping occurring at thevariableorifice restriction. Although either of the liquid dividers andflow controllers briefly discussed above may be applied in the apparatusof this invention and either may be compensated to eliminate liquid headeffects as hereinafter described, the latter modification is preferredin cases where improved linearity of liquid rate variation with appliedpressure is desired at low flow rates, or positive seating action of thevalve element is desired.

The structural detail of the apparatus of this invention and the methodin which it is used to obtain the results outlined above will be morereadily understood with reference to the accompanying drawings in which:

Figure l is a semi-schematic side elevation of a moving vehicle adaptedto carry the liquid distribution system of this invention,

Figure 2 is an elevation view taken at right angles to that in Figure 1and showing the transverse tool bar, injection shanks, liquid dividerand regulator elements, and the means for compensating for elevationdifferences,

Figure 3 is a schematic view of the apparatus in Figure 2 when operatedin an inclined position as on a hillside and indicating the variousliquid heads which ordinarily cause undesirable variations in theindividual liquid flow rates,

Figure 4 is a detailed elevation view in cross section of the liquiddivider and flow controller device, and

Figure 5 is a graph showing the linear flow rate variation with pressureand the effect of the employment of a primary and a secondary loadingspring.

Referring now more particularly to Figure l, a trailer provided withwheels 12 is drawn through. tow bar 14 by means of any suitable piece ofmoving equipment not shown. A farm tractor or the like is obviouslysuitable for this purpose. A storage tank 16 provided with filling hatch18 is disposed on trailer 10. Dispensing pump 20 is connected throughinlet line 22 to tank 16. Although pump 20 may be provided with its ownprime mover, such as a small gasoline enginenot shown, it is preferableto connect it through a variable drive means, also not shown, to trailerwheels 12 or a separate wheel riding on the ground by a chain drive 24or the like. Suitable pulleys of different diameters or other equivalentmeans are available to vary the ratio of pump impeller revolutions totrailer wheel revolutions, or a pump with integral variable outputcontrol may be used. In this way the volume of liquid dispensed in agiven distance traveled or per acre covered may be maintained at anypredetermined value.

The pump output is connected through line 26 to a lateral distributionor supply manifold 28 (the end of which only is shown in Figure l) towhich is connected a plurality of liquid flow dividers and controllers30. The rear end of the trailer is provided with a transverse tool bar32 which is connected to the trailer by means of clamps, a plurality ofvertical support bars 36, and linkages 33 and 40 to the rear of thetrailer. Any suitable mechanical means for raising and lowering thisassembly relative to the trailer, such as pneumatic cylinder 42, may beemployed. Such means are conventional and well known to those skilled inthe art. Transverse distributor manifold 28 is also supported from thesame movable assembly that supports tool bar 32, and is connected toliquid outlet line 26 through a flexible conduit;

A plurality of injection shanks 44 is clamped by means of clamps 34 totool bar 32. These are preferably bars of spring steel, either round orsquare in cross section, having a thickness of the order of 0.75 toabout 1.25 inches, and formed into the shape shown in Figure 1. Thisshape includes one or more helical turns indicated generally at 46. Theend of the injection shank is provided with ashoe 48 disposed when inuse below'ground level 50[ The rearward portion of shoe 48 is provided 6withan opening 52 into which liquid is introduced for direct dischargeinto the ground. Each shoe is connected by means of a pipe 54 and aflexible conduit 56 to one outlet port of one of the liquid dividers 30.

As the equipment above described is drawn along the surface of theearth, liquid is pumped from tank 16 through lines 22 and 26 at a ratedetermined by the velocity of the trailer along the ground surface. Thisliquid is passed through manifold 28 into a plurality of liquid dividers30 wherein a plurality of individual liquid streams are produced. Eachof such liquid streams is then passed through conduits 56 and 5d into anindividual injection shank for underground application. It may bereadily understood that if the view in Figure l were taken down hill,that the pressure applied to the lowermost flow divider 30 would begreater than that applied to the uppermost divider by an amount equal tothe differential liquid head in the supply manifold between the two.Since the degree to which the orifice openings are exposed to producethe individual liquid flows is governed by the liquid pressure at thedistributor inlet, it may be seen that the individual flows from thelower distributor will also be greater than those from the higherdistributor unless the compensation means of this inven tion isemployed.

Referring now more particularly to Figure 2, an elevation view taken atright angles to the apparatus in Figure l is shown. Herein transversetool bar 32, injection shanks 44 and shoes 48 connected thereto areshown. The transverse supply manifold 23 is also shown extendingequidistant from supply point 66 to the inlets of a pair of liquid flowdividers 62 and 64 which correspond to element 30 indicated generally inFigure 1. In the apparatus shown, a plurality of sixteen injectionshanks and shoes are employed and each liquid divider feeds eightindividual shanks. The lines connecting each shank are indicatedgenerally as 56 as indicated in Figure l and open downwardly along therearward portion of the injection shanks through conduits 54. Supplypoint 60 denotes the point at which pump outlet conduit 26 opens intothe midpoint of manifold conduit 28 indicated in Figure 1. At this pointthe flow divides into two streams, each one going to each liquiddivider, and from each of which eight individual streams are supplied tothe injection shanks as shown.

Across the midsection of dividers 62 and 64 is a diaphragm integrallyconnected to the movable valve element referred to above and which isdetailed in Figure 4 described below. The fluid to be divided issupplied below the diaphragm and the individual liquid streams are alsosupplied from the divider below the diaphragm. The space above thediaphragm in each flow divider is connected respectively throughequalizer conduits 66 and 68 to the bottom of a compensating reservoir71 which is normally open to the atmosphere through port 72. Reservoir70, lines 66 and 68, the upper portions of dividers 62 and 64, and thelower portion of reservoir '70 contain a compensating liquid having aspecific gravity substantially equal to that of the liquid beingdispensed. The compensating system is filled with this liquid to anextent that liquid level 74 in reservoir 7% lies at the same elevationas the diaphragms in dividers 62 and 64 when the entire apparatus is onlevel ground. It is also neces sary that all air or vapor be eliminatedfrom this system, and the arrangement should be such that any vaporsformed are free to vent themselves through the conduits into thereservoir 7i). When the device in Figure 2 is drawn along a hillside sothat tool bar 32 and manifold 28 are inclined, the compensating liquiddifferential head counterbalances the liquid differential head inmanifold 28 so that the net pressure differential across the dia phragmin each of the liquid dividers is equal at all times regardless of theattitude of the equipment. This counterbalancing effect is more clearlyillustrated in Figure 3 in which the apparatus of Figure 2 is'schematically shown in an inclined position.

Referring now to Figure 3, the operation of the compensating system isshown. Herein supply point 60, compensating reservoir 70, liquiddividers 62 and 64, transverse manifold conduit 28, and compensatingconduits 66 and 68 are shown as in Figure 2.. The eight branch conduitsopening from dividers 62 and 64- have been eliminated from Figure 3 forsake of clarity.

In the system shown Pm and P172 are the gauge pressures at the bottomsof the diaphragms in dividers 62 and 64 respectively. Pm and Pt2 are thegauge pressures above the diaphragms in dividers 62 and 64 respectively.P5 is the supply pressure at supply point 60. P: is the frictionalpressure drop in each half of manifold conduit 28 between supply point60 and the fluid inlet at the bottom of dividers 62 and 64 resultingfrom the fluid flow therethrough. Pa is the datum pressure of thecompensating system in the upper portion of reservoir 70. This isordinarily atmospheric pressure but may be any other pressure asdesired. APi and AP3 are the equivalent pressures due to static liquidheads I11 and 113 in manifold conduit 28 between supply point 60 and thediaphragms in dividers 62 and 64 respectively. APz and Al are thepressures equivalent to the static liquid heads In and 11 in thecompensating system in lines 66 and 68 respectively.

With the system level as indicated in Figure 2 the followingrelationships have been found to exist between the pressures andpressure differentials listed:

The pressures below and above the diaphragms are:

The net diaphragm pressure is:

and since by symmetry of physical arrangement [11:11 and 112 114 for thelevel system, or

at all how rates.

Since the outlet flow from the distributor is directly proportional tonet diaphragm pressure, Q=K(Pb-Pt), then the flows are equal.

When the system is inclined as indicated in Figure 3 the followingrelationships exist:

The pressures below and above the diaphragms are:

Then

AP1AP2= AP3+AP4 and AP1Pa AP2= -AP3 -Pa+AP4 which is the same result asfor the system in a level position.

Therefore, the gravity head differences are completely compensated inthe apparatus described and changes in inclination have no effect uponthe liquid fiow rate of the individual streams. This has been borne outby comprehensive testing of the equipment under actual operatingconditions.

It is therefore apparent that the liquid flow rates discharged inindividual streams from each liquid divider are equal to the flow ratesof individual streams discharged from all other liquid dividers at otherelevations. Accordingly the present device installed on moving farmequipment can be drawn across level land or along hillsides in eitherdirection and at all times the equipment will discharge a plurality ofstreams at rates which do not vary with the change in attitude of theequipment.

Referring now more particularly to Figure 4 the structural detail of thehow divider and regulator is shown. This device consists essentially ofa pressure resistant body portion 76 and a cap or upper portion 78 whichis secured by means of cap screws 80. The body portion is provided witha lower fluid inlet channel 82 threaded at its end to receive standardpipe fittings. A plurality of between about four and twelve orifices 84open radially from the inlet channel and are also provided with threadedportions for pipe attachment. The actual number of outlets is limited bythe physical sizes of the inlet chamber and the orifices. In the pilotmodels, 8 outlets were used. Movably disposed within the fluid inletchannel is valve element 86 shown in the seated position at whichorifices 84 are closed. The upper portion of valve element 86 isprovided with a spindle 88 which is threaded to receive nut 90 wherebywasher 92 is clamped against diaphragm 94 and lower washer 96 at the topof the valve element.

Diaphragm 94 sealed between body and cap elements 76 and 78 effectivelydivides chamber 98 contained within the cap and body element combinationinto a lower portion 100 and an upper portion 102. The lower space 100communicates through apertures 104 with the lower portion of fluid inletchannel 82 at a point below valve element 86. In this way the inletpressure is exerted not only against the lower surfaces of the valveelement but also against the lower surface of diaphragm 94 tending toraise the valve element and open the orifices. Slots 106 are milled inthe lower periphery of valve element 86 opposite each orifice 84 and maybe of any desired shape so as to obtain the required change in open areawith valve element travel.

Disposed within upper chamber 102 are primary loading spring 106 andsecondary loading spring 108 in coaxial relationship to one another. Theloading springs rest on the upper surfaces of the movable valve elementand tend to resist valve element movements induced by the application offluid pressure in inlet channel 82. As described previously a clearance110 is provided between the upper end 112 of the spring and the loadingspring adjustment cap 114. Secondary spring 108, however, has no suchclearance and is maintained under light compression at all times. In oneexample of this invention designed to distribute aqueous ammonia atpressures between 0.1 and about 50.0 p. s. i. g., the secondary springconstant was 10 pounds per inch, while the primary spring constant was1,000 pounds per inch. A clearance of 0.080 inch when the valve wasclosed was provided by adjustment of cap 114. As shown the flow rate ofeach individual stream was linear with changes in pressure over itsentire range. The individual liquid streams were discharged at rateswhich were all within 13% of the mean value.

The upper space 102 comprises the space into which the compensatingfluid previously described is introduced soas "to nullifyeffectsof'hydrostatic head in the equipment of this invention. Loading springcap 114 is provided with a lock nut 116 to maintain clearance 110 at thedesired value to secure linearity at the lower ranges of inlet pressure.Cap 114 is also provided with a compensating fluid channel 118, fitting120, and compensating conduit 122. The latter conduit 122 corresponds toconduits 66 and 68 indicated in Figures 2 and 3. With this construction,the net force acting on movable valve element 86 tending to displace itfrom its seated position shown and to open the orifices 84 is thedifference between the fluid pressure Pb in inlet channel 82 and thepressure Pt of the compensating fluid in upper space 102. As the entireapparatus shown in Figures 2 and 3 is moved into an inclined position,the increase in inlet fluid pressure due to hydrostatic head is exactlycounterbalanced by an increase in hydrostatic head in compensating fluidwhereby the net pressure difference remains the same so that the degreeof orifice opening likewise remains the same. This has been discussedabove.

In Figure 5 is shown the linear relationship between the flow rate Q ofan individual liquid stream from a flow divider such as that shown inFigure 4. The solid line 124 indicates at its lower curved portion thatat very low pressures the valve closes at some finite minimum pressuregreater than Zero. The dotted portion 126 indicates the extendedlinearity secured by employing the primary and secondary loading springsystem as described above including the clearance 110 at one end of theprimary loading spring. The clearance 110 shown in Figure 4 isdetermined by testing the device and adjusting the clearance so that themovable valve element does not close until the inlet pressure drops tozero. At this point lock nut 116 is tightened and the flowcharacteristic of the device is completely linear as indicated in Figure5.

The device of this invention was tested through the ap plication ofaqueous ammonia of 24% concentration on hilly farm land by means of anapplicator having the same general structure as is shown in Figures 1and 2. This device had sixteen injection shanks spaced on sixteeninchcenters. The equipment was moved at a forward velocity of about 3 milesper hour, the feed pump was adjusted to supply aqueous ammonia throughthe injection shanks at a rate of 70 pounds of nitrogen per acre, andthe flow rates in individual shanks were checked as the equipment wasdrawn along both level and hilly land. With the compensator systemconsisting of reservoir 70 and compensating lines 66 and 68 connected tothe tops of two flow dividers which are detailed in Figure 4 theindividual flow rates were found to within :1% of the mean valueregardless of the change in slope of the tool bar and distributionmanifolds. With the compensation system disconnected and the tops of thecompensators left open to the atmosphere the flow rates of the lowereight shanks were found to be as much as 6% higher than the flow ratesof the upper eight shanks when the apparatus was drawn along the contourof a hillside. It is notable that at lower flow rates the deviationbecomes of increasing magnitude. In the present test the compensatingliquid employed was raw water, but by employing other liquids ormixtures selected on the basis of low volatility and specific gravitysubstantially equal to that of the aqua ammonia, the compensation can bemade perfect. 7

Although the present invention has been described as being adapted touse on moving farm machinery, it should be understood that the sameadvantages may be obtained as far as equality of flow is concerned inthe individual injection of liquids such as fertilizer solutions into aplurality of irrigation water streams flowing along contour lines atdifferent levels on a hillside. It should also be understood that thecompensation'system should be applied generally to neutralize theeffects of hydrostatic head and elevation in any flow division andcontrol sys- 10 tem of the type described. Obviously the present in-'vention is not intended to be restricted to the particular liquidsherein discussed for the principles are general and may be appliedgenerally to liquid distribution problems.

A particular embodiment of the present invention has been hereinabovedescribed in considerable detail by way of illustration. It should beunderstood that various other modifications and adaptations thereof maybe made by those skilled in this particular art without departing fromthe spirit and scope of this invention as set forth in the appendedclaims.

I claim:

1. An apparatus for dispensing a plurality of fluid streams bearing apredetermined volumetric relation to each other which comprises a fluidstorage vessel, a fluid inlet to said vessel, a manifold conduit, meansfor supplying fluid from said vessel to an intermediate point along saidmanifold conduit, a plurality of fluid divider and flow regulators, eachof said regulators comprising a pressure resistant body element providedwith a fluid inlet channel extending therethrough and a plurality oforifices opening from said channel through said body element, meansconnecting each inlet channel to said manifold conduit, a valve elementmovably disposed in each inlet channel, a loading spring system biasingsaid valve element into a position closing said orifices whereby thepressure of fluid supplied said inlet channel from said manifold conduittends to move said valve element and open said orifices and permit flowtherethrough, a plurality of conduits connecting the outlet ends of saidorifices to fluid delivery points, a compensating fluid reservoir, and acompensating fluid conduit connecting said reservoir with each of saidfluid regulators at points on the opposite side of said valve elementsfrom said fluid inlet whereby the net fluid pressure tending to movesaid elements is independent of differential fluid heads in saidmanifold conduit.

2. An apparatus according to claim 1 in combination with a wheeledvehicle supporting said storage vessel, said manifold conduit, and saidfluid dividers, in combination with a pump comprising said means fordelivering said fluid to said manifold conduit, and a variable speeddrive connecting said pump to a wheel riding in contact with the groundadapted to deliver a volumetric rate of fluid from said pump that isproportional to the speed of said vehicle.

3. An apparatus according to claim 2 in combination with an elongatedtool bar supported transverse to the direction of travel of saidvehicle, a plurality of injection shanks supported at spaced intervalsalong said bar and adapted to be extended downwardly to subsurfacepoints, said manifold conduit being supported generally parallel to saidtool bar, and said delivery points being disposed .at the lower ends ofsaid injection shanks thereby permitting uniform fluid injection fromeach shank regardless of any differential head eflects induced in saidmanifold conduit by the inclination thereof.

4. An apparatus according to claim 1 in combination with a cap portionattached to said body element, a flexible diaphragm connected to saidvalve element and sealably secured at its periphery between said cap andbody portions, and a threaded insert at the end of said cap portion andcomprising an adjustable stop for said loading spring system and havingan opening through said insert for communication with said compensatingconduit.

5. An apparatus according to claim 4 in combination with a primary and asecondary loading spring disposed and said valve element, said primaryspring having spring constant in pounds per inch of deflection of fl'rbetween the opposing surfaces of said adjustable stop/ being adjustedsothat at zero inlet fluid pressure s, valve element is biased in aclosed position by sli} compression of said secondary spring while aclearar A 10 to times that of said secondary spring, said s1 11 existsat one end of said primary spring and whereby a substantially linearvariation in volumetric flow rate of the several individual streams fromsaid'regulator with changes in inlet pressure is obtained.

6. An apparatus for the uniform dispensing of a liquid at a plurality ofspaced points which comprises a movable vehicle, a liquid storage vesselsupported thereon, a liquid inlet thereto, a liquid pump connected atits inlet to said vessel, means for driving said pump at a rate which isa predetermined function of the velocity of said vehicle, an elongatedmanifold conduit disposed transverse to said vehicle, a conduit openingfrom the outlet of said pump into an intermediate point of said manifoldconduit, an elongated tool bar supported from and transverse to saidvehicle, a plurality of injection shanks supported from spaced pointsalong said tool bar and adapted to be extended to subsurface points, aplurality of liquid flow dividers, said dividers comprising a bodyelement having a central fluid inlet channel and a plurality of lateralorifices opening therefrom, a movable valve element disposed within saidinlet channel, a hollow cap element sealably secured to said bodyelement, a flexible diaphragm secured at its periphery and disposed in atransverse position between said cap and body elements and attached atits center to said valve element, a loading spring system disposedwithin said cap element and adapted to bias said valve element toward aposition at which the inlet ends of said orifices are sealed, means forconnecting said inlet channels to said manifold conduit whereby liquidpressure therein tends to move said valve element against said loadingspring system and open said orifices, a plurality of conduits connectingthe outlet end of each of said orifices to one of said plurality ofinjection shanks, a compensating liquid reservoir disposed on saidvehicle, and a compensating conduit connecting the lower part of saidreservoir with the cap element of each of said liquid flow dividers,said compensating reservoir and conduits containing a liquid having alow volatility and substantially the same specific gravity as that ofthe liquid being dispensed whereby the net liquid pressure acting onsaid valve element and diaphragm to open said orifices and the liquidflow rate therethrough is substantially unaffected by the inclination ofsaid tool bar and manifold conduit from the horizontal.

7. An apparatus according to claim 6 wherein said compensating liquidreservoir is located at a level whereby it is adapted to be filled withsaid compensating liquid to a level substantially the same as the levelof said diaphragms in said flow dividers when the manifold conduit is ina horizontal position.

8. An apparatus according to claim 6 wherein said means for driving saidpump comprises a variable direct drive between the pump impeller and awheel attached to said vehicle and riding in contact with the groundwhereby a proportionately greater rate of'liquid is pumped as thevehicle speed is increased.

9. An apparatus according to claim 6 wherein said cap element isprovided at its end opposite from said body element with a threadedadjustable insert having an opening through which said compensatingconduit opens into said cap element, said loading spring systemcomprising a primary and a secondary loading spring concentric with eachother and extending substantially between the inside surface of saidthreaded insert and said valve element, said primary spring having aconstant in. pounds per inch deflection of between about 10 and about100 times that of said secondary spring, and said threaded insert beingadjusted and locked in a position so that with a zero liquid pressure insaid inlet channel the secondary spring lightly seats said valve elementin the closed position and a clearance exists at one end 'of saidprimary loading spring whereby a substantially linearvariation in liquidflowrate to each injection shank with applied liquidpressure isobtained.

. 10. An apparatus for dividing a fluid stream into a plurality of fluidstreams bearing a predetermined volumetric flow rate relation to eachother which comprises a pressure resistant body element provided with afluid inlet channel extending therethrough and a plurality of orificesopening from said channel through said body element, a valve elementmovably disposed in said inlet channel, a loading spring system biasingsaid valve element into a position closing said orifices whereby thepressure of fluid supplied said inlet channel from said manifold conduittends to move said valve element and open said orifices and permit flowtherethrough, a plurality of conduit-s connecting the outlet ends ofsaid orifices to fluid delivery points, said loading spring systemcomprising a primary loading spring having a constant of between 10 andtimes that of a secondary loading spring and which is adjusted so thatsaid secondary spring lightly seats said valve element and relieves saidprimary spring of compression with zero applied fluid pressure wherebythe delivery rates are substantially linear with changes in inletpressure.

11. An apparatus for dividing a liquid stream into a plurality of liquidstreams having a predetermined flow rate relation which comprises a bodyelement having a central fluid inlet channel and a plurality of lateralorifices opening therefrom, a movable valve element disposed within saidinlet channel, a hollow cap element sealably secured to said bodyelement, a flexible diaphragm secured at its periphery and disposed in atransverse position between said cap and body elements and attached atits center to said valve element, a loading spring system disposedwithin said cap element and adapted to bias said valve element toward aposition at which the inlet ends of saidorifices are sealed, saidloading spring system comprising a primary loading spring having aconstant of between 10 and 100 times that of a secondary loading springand which is adjusted so that said secondary spring lightly seats saidvalve element and relieves said primary spring of compression with zeroapplied fluid pressure whereby the delivery rates are substantiallylinear with changes in inlet pressure, a source of liquid under pressurecommunicating with said inlet channel whereby liquid pressure thereintends to move said valve element against said loading spring system andopen said orifices, means for applying to the space within said hollowcap a fluid pressure to compensate for hydrostatic head effects of thesource of fluid, and a plurality of conduits connecting the outlet endsof said orifices to a plurality of delivery points.

12. An apparatus for delivering from a single stream under pressure aplurality of fluid streams at different elevations which comprises afluid storage vessel, a fluid inlet to said vessel, an elongatedmanifold conduit, means for supplying fluid from said vessel to saidmanifold conduit, a pluralityof fluid divider and fiow regulators, eachof said regulators comprising a pressure resistant body element providedwith a fluid inlet channel extending therethrough and a plurality oforifices opening from said ch annel through said body element, meansconnecting each inlet channel to said manifold conduit at differentpositions along the length of said manifold conduit, a valve elementmovably disposed in each inlet channel, a loading spring system biasingsaid valve element into a position closing said orifices whereby thepressure of fluid supplied said inlet channel from said manifold conduittends to move said valve element and open said orifices and permit flowtherethrough, a plurality of conduits connecting the outlet ends of saidorifices to fluid delivery points, a compensating fluid reservoir, and acompensating fluid conduit connecting said reservoir with each of saidfluid regulators at points on the opposite side of said valve elementsfrom said fluid inlet thereby applying to said valve element adifferential head of compensating fluid substantially equal and oppositeto the differential head of fluid'being.dispensed'insaid manifoldconduit when said 13 manifold conduit is inclined from the horizontal sothat the net fluid pressure tending to move said elements is independentof such inclination.

13. An apparatus according to claim 12 in combina* tion with a primaryand a secondary loading spring dis posed between the opposing surface ofan adjustable stop and said valve element, said primary spring having aspring constant in pounds per inch of deflection of from 10 to 100 timesthat of said secondary spring, said stop being adjusted in positionrelative to said body element so that at zero inlet fluid pressure saidvalve element is biased in a closed position by slight compression ofsaid secondary spring while a clearance exists at one end of saidprimary spring and whereby a substantially linear variation involumetric flow rate of the several individual streams from saidregulator with changes in net differential pressure across said valveelement is obtained.

14. An apparatus for delivering a plurality of liquid streams ofpredetermined flow rate relation at a plurality of diflerent elevationswithout hydrostatic head effects which normally aflYect the liquid flowrate which comprises an elongated manifold conduit disposed along anincline, a liquid supply conduit opening thereinto, a plurality ofliquid flow dividers disposed along the length of said manifold conduit,said dividers comprising a body element having a central fluid inletchannel and a plurality of lateral orifices opening therefrom, a movablevalve element disposed within said inlet channel, a hollow cap elementsealably secured to said body element, a flexible diaphragm secured atits periphery and disposed in a transverse position between said cap andbody elements and attached at its center to said valve element, aloading spring system disposed within said cap element and adapted tobias said valve element toward a position at which the inlet ends ofsaid orifices are sealed thereby, means for connecting said inletchannels to said manifold conduit whereby liquid pressure therein tendsto move said valve element against said loading spring system and opensaid orifices, a plurality of conduits connecting the outlet ends ofsaid orifices to a plurality of liquid delivery points, a compensatingliquid reservoir disposed along the length of said manifold conduit, anda compensating conduit connecting said reservoir with each cap elementof each of said liquid flow dividers, said compensating reservoir andcompensating conduits containing a liquid of low volatility and havingsubstantially the same specific gravity of that being dispensed wherebythe net liquid pressure acting on said valve element and diaphragm toopen said orifices and the rate of liquid flow induced thereby issubstantially unaifected by the inclination of said manifold conduit.

References Cited in the file of this patent UNITED STATES PATENTS

